Kaolinitic calcined clays: Factors affecting its performance as pozzolans

Tironi, Alejandra; Trezza, Mónica Adriana; Scian, Alberto N.; Irassar, Edgardo F.

doi:10.1016/j.conbuildmat.2011.08.064

Cited by 198 publications

(130 citation statements)

References 16 publications

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“…However, they have good pozzolanic activity when calcined at temperatures between 600 and 900 °C and ground to cement fineness (3,4). The ceramic industry generates a large volume of calcined clay wastes (up to 3% of production depending on producer and country).…”

Section: Introductionmentioning

confidence: 99%

Portland blended cements: demolition ceramic waste management

et al. 2017

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Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement. RESUMEN:Cementos Portland con adiciones: manejo de residuos cerámicos de demolición. Se estudiaron residuos cerámicos de demolición (DCWs) a fin de determinar su potencial uso como materiales cementicios suplementarios en cementos mezcla (PBC). Para este propósito, se investigaron tres residuos cerámicos. Luego de la caracterización de los materiales a utilizar, se analizó el efecto del reemplazo por residuos cerámico (8, 24 y 40% en peso). Se estudió la actividad puzolánica, el progreso de la hidratación, la trabajabilidad y la resistencia a compresión a 2, 7 y 28 días. Los resultados mostraron que los residuos molidos se comportaron como fillers a edades tempranas, pero con el progreso de la hidratación, la actividad puzolánica de los residuos cerámicos contribuye a los requerimientos de resistencia.

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Section: Introductionmentioning

confidence: 99%

Portland blended cements: demolition ceramic waste management

et al. 2017

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“…Quartz was the main crystalline phase in sand A, which , also from quartz (30,32). These bands were clearly visible on the spectra for sands B, C and D as well.…”

Section: Mineralogical Analysismentioning

confidence: 66%

PCE and BNS admixture adsorption in sands with different composition and particle size distribution

et al. 2017

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ABSTRACT:The choice of a superplasticiser (SP) for concrete is of great complexity, as it is well known that properties of the end product are related to admixture and its compatibility with concrete components. Very few studies have been conducted on the compatibility between SPs and the sand of mortars and concretes, however. Practical experience has shown that sand fineness and mineralogical composition affect water demand and admixture consumption. Clay-containing sand has been found also to adsorb SPs, reducing the amount available in solution for adsorption by the cement. This study analysed the isotherms for PCE and BNS superplasticiser adsorption on four sands with different fineness and compositions commonly used to prepare mortars and concretes. BNS-based SP did not adsorb on sands, while PCE-based admixtures exhibited variable adsorption depending on different factors. The adsorption curves obtained revealed that the higher the sand fineness, the finer the particle size distribution and the higher the clay material, the greater was PCE admixture adsorption/ consumption. RESUMEN: Adsorción de aditivos PCE y BNS en arenas con diferente composición y distribución de tamaño departículas. La elección de un superplastificante (SP) para el hormigón es un proceso complejo, ya que las propiedades del producto final se relacionan con la naturaleza del aditivo y su compatibilidad con los componentes del hormigón. Sin embargo hay pocos estudios sobre la compatibilidad entre los SPs y arenas utilizadas en morteros y hormigones. En la práctica se ha demostrado que la finura y la composición mineralógica de la arena afectan a la demanda de agua y al consumo de SPs. Las arcillas que pueden encontrarse en las arenas pueden también adsorber aditivos, reduciendo la cantidad disponible en solución para la adsorción por el cemento. Se han analizado las isotermas de adsorción para SPs de tipo PCE y BNS en cuatro arenas de diferente finura y composicion comúnmente utilizado para preparar morteros y hormigones. El aditivo BNS no se adsorbe en las arenas, mientras que los PCE mostraron adsorción variable. Las curvas de adsorción revelaron que cuanto mayor es la finura de arena, menor la distribución del tamaño de partícula y mayor el contenido de arcilla mayor era adsorción/intercalación de aditivos PCE en las arenas.

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“…Figure 10 shows a few stress-strain curves for the cement-treated Shanghai clay under the confined compression test (a c = 15 %, D = 28 days). As noted by many previous investigations (Chakchouk et al 2009;Tironi et al 2012), the increase in strength with cement content is due to the cement hydration leading to the pozzolanic products, which can bind together the clay particles or clusters of clay particles, and create a stronger structure. Furthermore, owing to the fact that the process of cement hydration and the consequent pozzolanic reaction can last for a long time, it can be expected that the UCS of treated soil increases with curing time.…”

Section: Unconfined Compressive Strengthmentioning

confidence: 89%

Rapid field evaluation of the strength of cement-stabilized clayey soil

Wang

Yin

2014

Bull Eng Geol Environ

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This paper presents an investigation into the hardness and unconfined compressive strength (UCS) of cement-stabilized Shanghai clay. Various specimens with different cement content and curing time were made in order to conduct hardness tests and unconfined compression tests. The Shore-A durometer was used in a pioneer manner to measure the hardness of stabilized clay. Hardness tests suggest that the measured values of degree of hardness ranged from 1 to 87 DH, and the unconfined compression tests showed that the measured UCS varied from 56 to 1,061 kPa. Test results indicate that the average degree of hardness decreases dramatically with an increase in the clay-water/ cement ratio. It is shown that the relationship between the degree of hardness and the curing time is approximately linear in the semi-logarithmic plot. An exponential equation is proposed to express the unique relationship between the UCS (q u ) and the ratio of degree of hardness (S/S r ) by regression analysis. The expected prediction range of UCS using the Shore-A durometer was calculated to be between 0.04 and 1.79 MPa. The exponential equation proposed in this study may be used to produce a quick prediction of UCS by measuring the hardness of samples in the field.

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Kaolinitic calcined clays: Factors affecting its performance as pozzolans

Cited by 198 publications

References 16 publications

Portland blended cements: demolition ceramic waste management

Portland blended cements: demolition ceramic waste management

PCE and BNS admixture adsorption in sands with different composition and particle size distribution

Rapid field evaluation of the strength of cement-stabilized clayey soil

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